Deloy,
Sorry you are having problems on your trip. Since I am the former owner of your coach (#307), I thought I would chime in.
I understand that all three AC units feed into the same plenum. Therefore if one, or two, were NOT working, there would still be some air coming out. Obviously, the majority of air in an area correlates to the nearby unit. So it is possible one unit is not getting power. Breakers? Line voltage?
Also, Royale set that coach up so either the mid or back unit would run off the inverter (there is a switch on the dash to select which one). I was hesitant to load up the inverters like that, so I never used that feature. It could be something in that circuitry.
My brother also has a Royale, his got to where he had to unplug the RJ11 (phone type) connector behind the filter on the AC unit to reset the thermostat to get it to work. I guess it is possible your problem is similar. He ended up replacing t-stats and controller board.
Is there a chance the filters are blocked?
I am sure others will have better ideas, but this might help you get started.
Did you get the fridge working?
John & Janene Browder
Knoxville, TN
2008 Marathon H3-3S